Hi, my name is Subhrendu Gangopadhyay. I'm a hydrologic engineer at the
Bureau of Reclamation's
technical service center in Denver. In this video
we'll step through the process of retrieving climate and hydrology projections data
for impacts analysis using the Downscaled Climate and Hydrologic Projections
website.
This site is a result of collaboration
between several federal and non-federal partners.
In a previous video I talked about necessary background information
for using this site effectively. Now I'm going to give you
a tour of the site and how to put together a data request.
Before getting into any of the site's detail
Please note the browser recommendations. Let's start with the Welcome tab.
Here we have a summary, purpose and history of the archive.
Check here for which data sets are currently available.
Here on the About tab, we provide
information archive development drivers and motivation, scope of the archive
contents
and projection attributes. We recommend you check this
area periodically for information on updates
and changes to the site. Here on the Climate sub-tab
we have a list of the attributes available for
each downscaling approach. These include variables,
time and space. Note the different coverage
and scope available for each of these
approaches. The documentation
and notes here provide some background on the currently available
projections. On the Hydrology sub-tab
we have a description of the attributes and
approaches used for developing hydrology projections
from climate projections. Here
we describe the modeling scope
and domain of the available downscaled projections.
Here, we outline
the available attributes to be chosen
for each downscaling approach. On the Tutorials tab
we provide examples of how to use projection output
from the site in actual analysis.
These tutorials are organized
by downscaling approach, and provide examples
of data retrieval and use of that data in
impacts assessment. Next
we are moving into the substantive area of the projections site,
the Projections: Subset Request tab. This is the key area of the site
you will use to get projection data. There are ten steps
for getting projection data. These must all be completed
before submitting the request. The Form Status boxes
help track the steps. As they are completed,
each one will be highlighted. When you have completed the 10 steps
you will click the Submit Request button here.
Here on the right we have an
indicator of the file size of the data request.
Three factors determine the size
of the data request. One, the number of variables selected,
two, the time period and three
the spatial extent. If the size of the request
exceeds 100 percent then you will not be able to submit the request.
On the Page 1 sub-tab
we will set the temporal and spatial extent.
Here we will complete steps one
through three, time step and period ... domain
and spatial extent. You can choose
either climate or hydrology projections or a combination of the two.
I'm going to show an example using the Upper Colorado River Basin.
Now for the first step, labeled 1.1,
we look at time step and period. I'm going to choose the monthly time step
for January 1950 through December
2099. For step two,
labeled 1.2, I'll choose the Colorado basin for the domain.
In step 3, for the spatial extent
I'm going to use the tributary area for the Upper Colorado River Basin
defined by this latitude and longitude
which I'll paste here. This is the location of the Lee's Ferry gauge.
When I click map outlet location
this area appears on the map.
Clicking on the location marker shows me tributary
information. Also note that
there is help available for each step
by clicking on the question mark button.
Up here in the form status area, we now see that we have completed
the first three steps. Note the next step
is labeled 2.4 which indicates
page 2, step 4. Moving along
to page 2 will select we'll select our projection sets.
Here we see that because we selected monthly time steps,
only the monthly projections are available.
Let's select the BCSD-CMIP3-Hydrology-
monthly projection set here in step 4.
Now the corresponding sub-tab becomes available.
On this tab for step 5, we will select
our variables. Let's select Precipitation
and Total runoff.
In step 6 we will choose projections.
Note, a projection is a combination of emissions pathway
or scenario, climate model, and a run
with a given set of initial conditions.
The emission scenarios are in the three main columns.
Each row represents a climate model.
For each climate model and each emissions path
there are one or more climate model runs represented by the checkboxes.
Boxes that are grayed out represent unavailable runs.
The buttons along the top allow selecting or deselecting
all projections from each emissions path.
So, now we see on our Form Status,
that we have competed steps 1 through 6.
On page 3, starting with Step 7
we are going to choose an analysis for the projection data
or to simply extract the projection time series.
We will choose Statistics and Spatial Mean.
Certain statistics may not be available,
depending on what variables you have selected.
In step 8, we choose the output format
for our results. NetCDF is useful
for advanced users. We will choose ASCII text output.
In step 9, we provide our
email address to receive a notification
and link to download the requested data. Finally
In step 10 we ask that you provide some information
on how you will make use up that data requested.
This helps us track how well we are serving the needs
of our various communities. Before submitting, check the form status
to see if you have chosen all required variables.
you can return to each step by clicking on the form
status boxes. We recommend taking a moment to verify your selections
before submitting your request. When you click Submit
you will see as summary and another submit button
to click after verifying your choices. The request is not submitted
until you click the second submit button. After submission,
a message will appear with an estimated time for completion.
Looking up at the top level tabs,
the Projections: Complete Archives tab provides FTP
access to download any of the projection-specific
full coverage data sets available for you to work with directly.
Archives are posted
in NetCDF format. Accessing the data archives in this way
is recommended for advanced users only.
Use the form on the Feedback tab
to send us any questions or comments.
Check the FAQ first to see if an answer to your question
has already been posted. The Links tab
provides additional resources and background information.
The climate and hydrology model resources
on this site will be updated, so be sure to check back periodically.
Thanks for watching.